External fixation systems for use in repairing bone fractures are well known and are disclosed, for example, in U.S. Pat. Nos. 2,346,346, 4,535,763, and 4,920,959. Their purpose is to orient and immobilize sections of a fractured bone during a period of osteogenesis and healing. Such a system necessarily involves the use of fixation pins that are extended through the patient's skin into the bone sections requiring alignment and immobilization. Maintaining the pin entry points through the skin clean and free of infection are major objectives in the use of any external fixation system. At the same time, a dressing designed for that purpose must be readily removable, replaceable, and simple to apply in an effective manner regardless of differences in the length of fixation pins exposed between the entry slits and the mounting brackets of the device.
Pin-site shields or dressings are available which take the form of foam discs associated with attachment means such as clamping rings or clips. In one such construction, a foam disc is lined on one side with fabric and has its opposite side secured to a rigid plastic disc equipped with a set screw. A radial slit in the disc allows it to be fitted onto a fixation pin and, by tightening the set screw, the disc is then locked in place against the skin at the entry site. Such a device tends to be awkward to operate and lacks automatic means for exerting a controlled amount of dressing pressure at the wound site. Depending on just where the user tightens the set screw against the fixation pin, the force applied by the dressing against the wound site might be excessive, insufficient, or totally lacking. Furthermore, the complexity of such a two-piece construction--with one of the elements performing a dressing function and the other an attachment function--renders the device relatively expensive for a user who may, at least in some cases, be required to change the dressings at multiple sites two or more times a day.
Accordingly, an important aspect of this invention lies in providing a simple and inexpensive fixation pin entry site dressing, and its method of use, in which both the attachment and absorptive functions are performed by the same unitary element. Another important objective is to provide a dressing that may be quickly sized to suit the reception site and easily applied or removed from that site. Despite its ease of removability when wound inspection or dressing replacement is desired, the dressing is self-retentive and notably effective at remaining in place until removal is required. The dressing of this invention has been found particularly effective at absorbing exudate for preventing skin maceration, covering a pin site while at the time maintaining an open pathway to allow fluid to escape, protecting clothing and linens from exudate contact, and stabilizing the skin relative to a fixation pin, thereby preventing relative skin movement that could result in inflammation and predispose the site to infection.
In brief, the external fixation pin dressing of this invention takes the form of an elongate block of soft, compressible, liquid-absorbent material capable of being torn apart at any of a number of predetermined zones of separation with little or no fragmentation or free particle release. The block is composed of a multiplicity of connected segments, each segment being partially separated from adjacent segments by pairs of transverse slits extending inwardly from opposite sides of the block. A connecting septum joins each segment to an adjacent segment and each septum is tearable for disconnecting one segment, or a selected number of joined segments, from the remainder of the block.
In addition, the block is provided with a longitudinally extending primary slit that extends inwardly from one side of the block and, in a preferred embodiment, a longitudinal cross slit within the block that intersects the primary slit along the block's longitudinal mid-line. In applying a dressing, a user simply removes a selected number of segments from the block (the total length of the selected segment(s) being greater, when the foam is uncompressed, than the exposed length of fixation pin to be covered), then longitudinally compresses the selected segment(s) and fits it onto the exposed shaft of the pin immediately adjacent the entry site. When the dressing is properly in place, the pin extends through the dressing segment(s) along the intersection of the primary slit and the longitudinal cross slit. Since the applied dressing remains in a state of compression after being fitted about the shaft of the pin, it stabilizes itself in place and in firm contact with the skin surface surrounding the pin entry site, thereby accomplishing the objectives of covering the pin site and stabilizing the skin around that site.
Other features, advantages, and objects of the invention will become apparent from the specification and drawings.